David E. Steitz
Headquarters, Washington, DC September 17, 1998
(Phone: 202/358-1730)
Lynn Chandler
Goddard Space Flight Center, Greenbelt, MD
(Phone: 301/614-5562)
RELEASE: 98-170
SEAWIFS COMPLETES A YEAR OF REMARKABLE EARTH OBSERVATIONS
For the first time in history, NASA is releasing dramatic
images documenting the Earth's changing biology, both on land and
in the oceans, as observed from space for one continuous year.
The changing seasons of life, the "pulse of the planet," are
being monitored by the Sea-viewing Wide Field-of-view Sensor
(SeaWiFS), which was launched on Aug. 1, 1997, and has
continuously produced data since Sept. 18, 1997. The SeaWiFS
mission is the first NASA Earth Science data purchase in which
industry led the development of the full mission.
"Although originally designed to observe the oceans, SeaWiFS
provides a unique capability to study the land and atmospheric
processes as well," said Dr. Gene Feldman, oceanographer, who
heads SeaWiFS' data processing team at NASA's Goddard Space Flight
Center, Greenbelt, MD. "As a result, we can monitor changes in
the global biosphere with a single sensor over land and ocean."
Among the highlights of SeaWiFS' first continuous year of
observation were new insights into the impact of the El Ni–o
climate anomaly on ocean life. Further, SeaWiFS was able to
monitor a variety of natural disasters, including fires in
Florida, Mexico, Canada, Indonesia and Russia; floods in China;
dust storms in the Sahara and Gobi Deserts; and the progress of
hurricanes, such as Bonnie and Danielle.
SeaWiFS enabled scientists to witness the ocean transition
from El Ni–o to La Ni–a conditions in the Equatorial Pacific,
specifically around the Galapagos Island. The instrument also
allowed researchers to observe the striking speed with which the
ocean returned to its pre-El Ni–o state. While El Ni–o
essentially shut down the highly productive Equatorial Pacific
ecosystem, the subsequent La Ni–a resulted in unprecedented
phytoplankton blooms, which stretched across the entire basin from
the South American coast to the Western Pacific warm pool.
Phytoplankton are microscopic marine plants that remove
carbon dioxide from the atmosphere for internal use. Scientists
are eager to understand this exchange of carbon dioxide and the
role it plays in the global climate.
"One of the most fascinating events witnessed in the global
ocean was the Spring bloom in the North Atlantic," said Dr.
Charles McClain, SeaWiFS project scientist. "While many regions
of the ocean experience a spring bloom, the event in the North
Atlantic was the most dramatic."
During the winter, storms and surface cooling mix the surface
waters of the Atlantic, replenishing the nutrient supply from the
deep, cold, nutrient-rich waters. Once sunlight is sufficient to
support plant growth, phytoplankton populations explode and
persist for nearly three months until nutrients are depleted.
This bloom migrates northward following the Sun throughout the
spring and summer.
Unexpected phenomena observed by SeaWiFS, according to
McClain, were the massive blooms of coccolithophores, a unique
type of phytoplankton in the Bering Sea. These blooms may have a
significant impact on fish populations in this area, one of the
most productive fishery regions in the global ocean.
During the summer-fall of 1997 and spring of 1998, expansive
blooms of coccolithophores occurred along the Alaskan shelf.
These were the first observations of blooms of this magnitude in
the Bering Sea. Coccolithophores shed vast numbers of white
carbonate platelets which cloud the water. "The net result was
fish that normally spawn in the adjacent rivers could not
trasverse the bloom in order to enter the rivers to spawn. In
addition, local bird and marine mammal populations had a high
mortality rates due to starvation because the fish migrated to
other waters," said McClain.
NASA is leading an international collaboration using SeaWiFS
data. More than 800 scientists representing 35 countries already
have registered to use the data. There are over 50 ground-
stations throughout the world which receive data from the
spacecraft. In addition, the unique government-industry
partnership with ORBIMAGE, Dulles VA, represents a new way of
doing business for NASA.
SeaWiFS is an essential component of NASA's Earth Sciences
enterprise, an ongoing effort to study the changing global
environment. Using the unique perspective available from space,
NASA will observe, monitor and assess large-scale environmental
processes focusing on climate change.
Remarkable images from this mission are available on the
World Wide Web at URL: http://seawifs.gsfc.nasa.gov/SEAWIFS.html
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